mainlining shenanigans
50b045a8c0
One of the biggest issues we face right now with picking LRU map over regular hash table is that a map walk out of user space, for example, to just dump the existing entries or to remove certain ones, will completely mess up LRU eviction heuristics and wrong entries such as just created ones will get evicted instead. The reason for this is that we mark an entry as "in use" via bpf_lru_node_set_ref() from system call lookup side as well. Thus upon walk, all entries are being marked, so information of actual least recently used ones are "lost". In case of Cilium where it can be used (besides others) as a BPF based connection tracker, this current behavior causes disruption upon control plane changes that need to walk the map from user space to evict certain entries. Discussion result from bpfconf [0] was that we should simply just remove marking from system call side as no good use case could be found where it's actually needed there. Therefore this patch removes marking for regular LRU and per-CPU flavor. If there ever should be a need in future, the behavior could be selected via map creation flag, but due to mentioned reason we avoid this here. [0] http://vger.kernel.org/bpfconf.html Fixes: |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.